Gear-like indicator of stripped threads



u. c. KLAUSMEYER. GEAR LIKE INDICATOR 0F STRIPPED THREADS.

APPLICATION FILED JULY23, 192|. 1,415,005.

Patented May 2, 1922.

2 SHEETS-SHEET l.

A DO ATTORNEY` D. c. KLAusn/IEYER. GEAR LIKE INDICATOR OF STRIPPED THREADS. APPLICATION FILED JULY 23,v |921.

Patented May l2, i922.

[ETS-SHEET 2 STATES PATENT FFEQE.

DAVID C. KLAUSNIEYER, OF CINCINNATI, OHIO, ASSIGNOB T0 THE CINCINNATI BICKFORD TOOL COMPANY, 0F CINCINNATI, OHIO, A CORPORATION OF OHIO.

GEAR-LIKE INDICATOR OF STRIPPED THREADS.

iniaoos.

Application led July 23, 1921.

To all whom t may concern Be it known that I, DAVID C. KLAUsMEYER, a citizen of the United States, and residing at Cincinnati in the county of Hamilton and State of Jhio, have-invented a new and Improved Gear-Like Indicator of Stripped Threads, of which the following specification Vis a full disclosure.

This invention is addressed to the prevention of accidental drops of a member depending for its support on screw threads unduly worn by long usage or lack of lubrication, and it was contrived, in its more specific aspect, to safe-guard the user of a so-called radial-drill in which a heavy and complicated head is carried by a horizontally extending arm which, in turn, is elevated by a screw threaded through a nut. The nut is conventionally embedded in the arm and the elevation is effected by causing the screw to rotate; thereby bodily raising both the nut and the arm simultaneously.

This invention is predicated upon the proposition that, when the nut and arm are bodily translated as a'unit with respect to the screw, any other element carried by the arm (and at the same time in threaded engagement with the screw), and independently movable on said arm save for its engagement with said screw, will remain in unaltered relation with the nut so long, and only so long, as the normal relation between the nut and the screw is maintained. Should said normal relation be disturbed, however, either by undue wear or by the actual failure of the nut threads, the screw will (indepen'dently of its rotations) translate with respect to the arm, to the nut and to said movable element and will, so to speak, operate like a rackon said element and cause it to move relative to the arm on which it is mounted. This invention takes advantage of the aforesaid peculiarity by utilizing thev thus-effected movement of said element (lst) to arrest any further abnormal translation between the arm and the nut and (2nd) to give warning to the userof the untoward condition of the parts, either by displaying a signal or sounding an alarm or otherwise; as may be preferred.

In carrying forward this'conception, there are certain structural advantages in making use of a pivot, or a mounting involving an arcuate path, for the purpose of supporting the aforesaid element on the arm; in which Specification of Letters Patent.

Patented May 2, 1922.

Serial No. 487,067.

case the element may have its screw-engaging contour in the nature of a gear, or segment of a gear, having its pitch line concentric or eccentric with the center of rotation of the member, according to the ultimate result desired. Thus, in case no interference with the contmued rotations of the screw is desired, the concentric relation will be resorted to in conjunction with some suitable provision for arresting or braking the movement of said element. Should, however, it be desired also to terminate the rotations of the screw as soon as the nut has stripped, this invention may 'readily be adapted to that end by resorting to the eccentric relation for the purpose of exerting a wedge-like action on the screw and frictionally retarding its rotations; in which case the drive for the screw will embody some conventional safetyslip or safety-yield device, as will be understood.

The above-outlined objects of this invention will be better understood by refer ring to typical concrete examples; two of which are depicted in the accompanying drawings, of which:

Fig. l is a side elevation of a portion of the arm of a radial drill embodying this invention; the parts being depicted in their normal relations. Fig.` 2 is a similar view but showing the positions assumed by the parts to warn the user that the regular nut needs to be replaced owing to wear or the stripping of its threads.V Fig. 3 is a section taken through line 3 3 of'Fig. l showing further details in the mounting of the parts. Fig. 4 is a sectional plan of a modified application of this conception whereby the revolution of the screw is impeded in case of undue wear. Fig. 5 is an elevation of the parts forming said modification.

The primary objects of this auxiliary are (A) to hold the arm from falling and (B) to inform the user that the conventional nut is no longer fit for service; although the first exemplication is so devised that it may for a brief period serve as a temporary substitute for the unduly-worn regular nut. Depending upon' the proportioning and adjustment of the parts, the warning may be given either after the threads have actually stripped or occnr in the threads ot the nut.

here instanced as the arm of a radial drill. A rotatable lifting screw 2 extends upwardly, in a conventional manner, and is threaded through an ordinary nut 6 which is secured by means of a screw 7 in a socket 24 provided by a boss 25 interorly integral with the arm 1. The upper end of the nut rests against a shoulder 8 provided by said boss 25 and is thereby secured against movement.

rlhe element A is gear-like in form and consists ot a hub l() pivotally carried by a stub-shaft 9 appropriately mounted at its ends in the side-walls a and 5 of the arm. The element A provides an arm 11 which at its tree end terminates in a rim provided' with teeth 12; this rim being in the nature ot a segment of a worm gear in mesh with the threads of the screw. In thetorin shown by the Figs. 1 to 3, the teeth are located on a circular arc concentric with the axis of the shaft 9. lt will be seen that, so long as the threads on the nut remain rnworn7 there will be no movement of the element A withrespect to the nut; these two parts being` bodily movable together as a unit with the arm. Should wear ot the init-threads take place, the screw will. shift its position accordingly with respect to the nut and a corresponding movement of the element A will obtain. lt

' 1 will be noted that, inasmuch as the element. .A

exerts no pressure on the threads ot the screw (being sel'lpositioning so to speak), there will be no appreciable wear ot the threads or"r the element A and the latter will,

, therefore, be capable ot' being moved by this screw in true proportion to the extent ot the wear between the screw and the nut. Con-- sequent y, the position oi'' the element A will afford a true indication ot such wear may' This move4 ment will., however, be necessarily compara` tively slight and, if unmagnilied, might easilyv scape the notice of the user. This invention, accordingly, proposes the employ` ment ol an auxiliary indicator sensitive to comparatively slight movements of the element A. lllhile various arrangements ot this nature may readily bc provided, such tor example as an elongated pointer affixed to the element A, a simple and rugged device well suitable for the requirements of a machine-tool has been indicated on the drawings. This consists ota plate C secured to a rock-shaft 15 pivoted between the walls 4 and 5 ot the arm; the plate being arranged adjacent the outer tace ot the arm and normally covering an appropriate warning legend 23 imprinted on a slightly aised'boss 16 provided by the arm. rlhis plate is noi ma ly held in the position shown by Fig. 1

. by means of a sensitive catch opera ted by the element A. This catch comprises a trigger 1S nor nally engaging a notch 17 in the rock` shatt 15. By appropriately proportioning these parts, it will befseen that the plate or indicator C may be automatically released whenever the wear has taken place to a predetermined extent or whenever the threads of the nut have become stripped.

ln a. very simple manner, the element A may be utilized as a salety device having for its object the prevention of an abrupt descent oi the arm due to the stripping of the nut'- threads, To this end, a positive stop is arranged to limit the extent ot the movement oi the element A caused by its engagement with the threads of the screw. Thisv stop may consist of a lug B carried by a portion of ythe arm, suoli as the web 1st; said lug B being. located in the path ot a seat 181 pro.- vided by the element A. When initially installed, a slight clearance indicated by 2G will be provided between the lug B and the. seat 13, so that the element A may float with the screw to the extent of unobjectionable wear ot the threads of the nut. This clearance 26 will be such that thev indi-catorplate C will. be released before contact is eef tablished between the seat 13 and thelug. Bg. lt should not, however, be materially greater thanv the thickness ot the thread: of the nut, in order to minimize the shock im-v. posed on the threads of the elementl A in ab. ruptly arresting the tall of the arm 0ccasioned by a failure ot the nut. By'keep'- ing the clearance thus limited, the. threads ot the element A will serve as an emergency nut Yfor a limited period of time enabling the user ot the machine to continuer its. use lor a short time until the new nut can bef obtained and substituted.

ln the modilication represented by Figs. 4t and the element A is not intended to be used an emergency nut in so far as fun ther elevations ot thev arm are to be madef but vit does act as an emergency nut to the extent ol preventing the tall of the arm and locking the lifting screw against further ro` tations, thereby keeping the machineout. of service until a new nut has been substituted tor the inji'lred one. ln this modification, the element n. is also pivoted to a shaft 9 fixed to the arm, being provided with a hub- 21 ior that purpose. rlhe wing. 22 or' theV element fr has an arcuate peripheral tace.

provided with worm-teeth meshing with the threads ot the screw. Unlike the element fr in the lirst described form, the pitch line of these worm-teeth is not concentric with the axis ot' the shatt 97 but progressively increases its distance therefrom. in any suitable ratio, as indicated by Fig. ln consequence ot this pecnliarity, any movement oit the screw independently ol its threaded.- relation with the nut, will cause the part. El! to move clockwise and act as a wedge pressing its teeth forcibly against the threads ot the screw and vtrictionally retarding thek rotations ot the latter. rlfhis modiiication isl preferably used in conjunction with any one of the several eXpedients conventionally resorted to for the purpose of preventing the screw from being positively driven whenever the arm meets with some undue obstruction. Such devices are in the nature of frictional slip-clutches or in the form of replaceable shear-pins or in the form of intermediate gears arranged to jump out of mesh in the event of excessive duty requirements; the illustration of these being omitted since they are so wellknown.

It will, from the foregoing, be seen that this invention is well adapted to achieve its objects and will afford adequate safety on the part of users of the machine. It serves effectively to prevent the damage resulting from a failure of the nut and it may be used to give a clear indication of the condition of the nut-threads and may either be used alone or combined with other arrangements serving the latter purpose, if so desired. For example, the alarm may be given by means of a gong or any other suitable signal system.

Vithout further analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the essential characteristics of either the generic or specific aspects of this invention, and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims Having thus revealed this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the United States:

l. A machine-tool of the nature disclosed combining a frame element; a nut and screw cooperating to elevate said element; a gear-like member carried by said element and meshing with the threads of said screw and adapted to be moved thereby idependently of said element at the termination of the cooperation between the nut and screw; and means actuated by said member adapted to warn the user of the termination of the cooperation between the nut and the screw.

2. A safety device for elevating mechanisms comprising, in combination, the member to be elevated; a screw and a nut for elevating it; a part pivoted to said member and arranged to mesh with said screw, said part having a restricted rotation about its axis; and a warning device adapted to be actuated by a partial rotation of said part.

3. A safety device for elevating mechanisms comprising, in combination, the member to be elevated; a screw and a nut for elevating it; a part pivoted to said member and arranged to mesh with said screw, said part having a restricted rotation about its axis; and means for exhibiting a warning, said means being self-actuated and normally restrained by said part but releasable upon a movement of said part.

4. A drilling machine combining a radial arm; a nut non-translatably mounted on said arm; an elevating screw passing upwardly through said nut; a gear-like member pivoted to said arm in mesh with the threads of said screw and adapted to be rotated thereby in case said screw should be given a translation independently of its cooperation with said nut; and a signal device adapted to be operated by said member.

5. A safety-device of the nature disclosed combining a member adapted to be elevated; a lifting-screw threaded to said member; an element rotatably carried by said member and also in engagement with the threads of said screw; a stop provided by said member and spaced slightly from the abutment provided by said element; and a signal-giving means connected with said element and adapted to be actuated by a movement of said element insuflicient to establish contact between said stop and said abutment.

6. A safety-instrumentality of the nature disclosed combining a member adapted to be elevated; a lifting-screw threaded thereto; an element pivotally mounted on said member and providing teeth engaging said screw; and a self-acting signal device normally held out of action by an engagement with said element but adapted to be released by an angular movement of said element corresponding to a distance less than the thickness of a thread on said screw.

7. A drilling-machine combining a radial arm; a lifting-screw threaded therethrough; an indicator mounted on said arm; and means intervening between said screw and said indicator for enabling the latter to be actuated in case said arm has shifted along said screw a distance appreciably greater than that corresponding to the normal revolutions of said screw.

ln witness whereof, I hereunto subscribe my name, as attested by the vtwo subscribing witnesses.

- DAVD C. KLAUSMEYER. lVitnesses z C. C. Snare, L. G. KECK. 

